1. Field of the Invention
This invention is directed to an improved system of conserving steam and water in pasteurizers, as well as providing apparatus for reducing the cost of effecting pasteurization of beverages.
2. Description of the Prior Art
The need for pasteurizing beverages has been known for many years, principally for control of harmful germs in beverages, and to preserve product flavor and extend shelf life. The use of water sprays or showering means in pasteurizing apparatus of common ownership with the present application has been disclosed in the early patents of Herold et al U.S. Pat. Nos. 2,282,187, issued May 5, 1942, and 2,466,769 issued Apr. 12, 1949. Other types of pasteurizers are disclosed in Meyer 2,333,544 issued Nov. 21, 1943 and Tillman 3,622,357 issued Nov. 23, 1971.
A pasteurizer having a system for conserving energy by providing a source of heated water to reduce the use of steam has been disclosed by Huling in application Ser. No. 062,693, filed Aug. 1, 1979, now U.S. Pat. No. 4,263,254 issued Apr. 21, 1981. A further pasteurizer improvement for conserving energy by providing an auxiliary source of chilled water has been disclosed by Huling in application Ser. No. 097,511, filed Nov. 20, 1979, now U.S. Pat. No. 4,279,858 issued July 21, 1981. In these applications, the principal aim is limited for accomplishing a particular purpose.
The problems with these earlier forms of pasteurizers reside in the great size of apparatus, the cost of the energy to transfer heat and cooling to thousands of beverage containers, and the tremendous quantities of water and steam needed to carry out the necessary basic steps of heating, holding at pasteurizing temperature levels, and cooling. The cost of the energy used up on a single container is insignificant, but when it is figured up in terms of a pasteurizing process for handling large numbers of containers per hour, the energy cost becomes significantly high. For example, a pasteurizer rated to process 72,000 bottles of beer per hour can use steam at a cost as high as $25.00 per hour or $100,000 per 4000 hour year, and the water cost can be of the order of $21.00 per hour or $84,000 per year. These figures are applicable without regeneration.
Cost can be reduced if regeneration is incorporated as taught by Huling in the foregoing disclosures. In the normal case of beer entering the pasteurizer at a temperature level of about 34.degree. F, the containers absorb heat from water, cooling the water and raising the beer temperature toward pasteurizing levels. The cooled water is sprayed over the containers in the cooling zone after pasteurization to absorb the heat and cool the beer before discharge to the outside. A thermal balance is achieved, and the beer containers are discharged at a temperature level of the order of 80.degree. F. A perfectly balanced theoretical example could eliminate the water cost and cut the steam cost to about $13.60. The result would be reducing costs from about $184,000 to about $54,000 for a sayings of the order of $130,000 per year. A pasteurizer operating at about 85% efficiency is a more practical case to consider, but as that level there are "gaps" in the supply of containers which upset the thermal balance. When the gaps (or skippers) show up in the load end of the pasteurizer, cold water has to be used for lack of the cold beer. When gaps or skippers are present in the discharge end steam, has to be used to substitute for the lack of hot beer. Under conditions of this example, cost would rise and the quantity of containers would drop.